Launch BBC One North

[Markymark]

Wouldn't BBC1 and 2 be in sync with each other, considering they came (and still do) from the same timing reference?

Back in the day when I was a lad,  I'd often take a look at off air BBC 1 and 2 and measure their relative sync. They were usually well within a line of each other.
The only time they'd occasionally differ was when there was a long form sports event, normally on BBC 2, perhaps because the OB's SPG had drifted away from London's after a few hours?